JPH06314643A - Method and apparatus for switching optical filter and pattern reader using the same - Google Patents

Abstract

PURPOSE:To suitably read a pattern by utilizing an optical filter. CONSTITUTION:A code reader has a light source 41 for illuminating a wafer 1 formed with a code 9, and a television camera 35 for imaging the code 9, and comprises an optical filter switching unit 43 interposed between the source 41 and the camera 35. The unit 43 has a holder 47 having a plurality of disposed optical fibers 48a-48n, a motor 45 for rotating the holder 47, a position information display reader 62 disposed oppositely to the fiber, and a controller 46 for collating the filter by the reader 62 with an optical filter so designated as to be opposed to the source 41 to instruct a rotation of the motor 45 in the case of discordance. Thus, when the filter is switched by the unit, a reflected state is improved, and hence a best reading state can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for switching optical filters, and more particularly to a technique for switching a desired filter when a plurality of optical filters having different transmittances are arranged in a holder. The present invention relates to an effective one used for reading an identification code displayed on a semiconductor wafer (hereinafter referred to as a wafer) or a mark having a color (color) displayed on a product in a process.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process, an identification code (hereinafter, simply referred to as a code) unique to each wafer is displayed on a wafer for production management and data management, and the code is read as necessary. Is being done. The code displayed on the wafer is composed of a pattern of irregularities formed on the main surface of the wafer by the lithography process and the etching process.

As a code reading device for reading the code of the wafer thus constructed, an illuminating device for illuminating the wafer, a television camera for picking up an image of the illuminated code of the wafer, and an image signal of the television camera are used. And an image processing device for recognizing the code of the wafer.

Further, in the manufacturing process of a semiconductor device, generally, a mark indicating a product name, a model number or the like is displayed on the manufactured product. Further, in a product such as a diode, a mark having a color (hereinafter referred to as a color mark) is attached by using a different color for each kind. That is, each color is identified by this color mark. For example, a high-frequency diode displays a color mark in red, a low-frequency diode displays a color mark in blue, and a small signal diode displays a color mark in green.

On the other hand, in the process of manufacturing a semiconductor device,
In order to inspect whether or not the mark displayed on the product is properly displayed, the work of reading the mark is performed. If a person were to read the mark, the productivity would be extremely reduced, so that the mark is generally read automatically.

When the mark is displayed in color, the following mark reading method is implemented. (1) A mark reading method in which a color image processing device is used. That is, the color television camera images the mark, analyzes the amount of each primary color in each pixel, recognizes the color of the mark, and reads the mark having a specific color.

(2) A mark reading method in which an electronic filter type color extraction device is combined with a binary / grayscale image processing device. That is, the mark is imaged by the color television camera, and only the color extracted by the electronic filter is recognized, so that the mark having a specific color is read.

(3) A mark reading method in which an optical filter type color extraction device is combined with a binary / grayscale image processing device. That is, only the color of the mark extracted by the optical filter is imaged and recognized by the monochrome television camera, and the mark having the specific color is read.

An example of the optical inspection technique is “Electronic Materials 1987 11
"Month issue separate volume" issued November 20, 1987 P233-P
There are 239.

[0010]

However, in the above-mentioned code reading device, since the light emitted from the illuminating device is light in a constant wavelength band, the contrast of the image is good and the code is appropriate. The present inventor has clarified that there is a problem in that there is a case where the image is read and a case where the image has poor contrast and the code cannot be read properly.

This symptom is influenced by the type of semiconductor device manufactured by the wafer, the difference in the manufacturing process, the variation in each process, and the processing state (film thickness, film quality, etc.) in the wafer. I am affected by the variation. The reason why the symptom is affected by these is that the code is formed through the same process (lithography process) as the circuit pattern on the wafer, and the fluctuation of the film thickness and the fluctuation of the etching occur in the process. Is considered to be significantly affected by process variations after the code formation process.

A first object of the present invention is to provide a pattern reading technique capable of always reading a pattern properly.

Further, the above-mentioned color mark reading method has the following problems. First, the mark reading method in which the color image processing apparatus is used, the mark reading method in which the electronic filter type extraction apparatus is used in the binary and grayscale image processing apparatus has a problem that the structure is complicated and the cost is high. .

In a mark reading method in which an optical filter type extraction device is combined with a binary / grayscale image processing device, it is necessary to automatically and quickly switch an optical filter having a transmittance corresponding to a color mark.

Therefore, a plurality of optical filters transmitting different specific wavelength ranges are prepared, and the optical filters transmitting the specific wavelength range corresponding to the color marks can be automatically and quickly opposed to the illumination light source. Development of filter switching technology is desired.

A second object of the present invention is to provide an optical filter switching technique capable of switching the optical filters automatically and quickly.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0018]

The typical ones of the inventions disclosed in the present application will be outlined below.

That is, the holder is provided with a plurality of optical filters each having a different transmittance and arranged at different positions, and a moving means for optically moving the holder relative to the illumination device. Is an optical filter switching device in which the optical filter optically opposed to the lighting device is switched by being relatively moved with respect to the lighting device. The detecting means for detecting and the optical filter detected by this detecting means and the optical filter designated so as to face the lighting device are collated, and when both do not match, the holder is set to the lighting device to the moving means. And a controller that transmits a movement command to perform relative movement optically.

Further, in a pattern reading device including an illuminating device for irradiating a read object on which a pattern is formed with light, and a light receiving device for receiving reflected light from the read object, the illuminating device and the light receiving device are provided. The optical filter switching device according to the above-mentioned means is interposed between the device and the device.

[0021]

According to the above-mentioned second means, when the reading state of the pattern is bad, the optical filter switching device interposed between the illuminating device and the light receiving device allows
When the optical filter through which the irradiation light is transmitted is switched, since the transmittance of the irradiation light in the optical filter is changed after the switching, the reflection state from the pattern of the irradiation light is modulated compared to before the switching. The reading state of the pattern will be changed and adjusted. Therefore, the optimum reading situation can be created by appropriately switching the optical filters.

According to the above-mentioned first means, when the optical filter to be switched is designated when the optical filter is switched, the switching operation of the designated optical filter is automatically and properly performed, and the switching operation is short. Since it can be performed in time, the optical filter switching operation can be performed very efficiently and highly accurately.

[0023]

1 is a schematic view showing a code reading apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view thereof. FIG. 3 is a front sectional view showing an optical filter switching device which is one embodiment of the present invention used in the code reading device. Figure 4
Is a flow chart diagram thereof. 5 is a plan view showing the wafer, and FIG. 6 is a perspective view showing the wafer cassette. Figure 7
(A), (b) is each explanatory drawing for demonstrating a code reading action.

In this embodiment, the pattern reading device according to the present invention is constructed as a code reading device for reading an identification code attached to a wafer. As a general rule, a plurality of wafers 1 which are the object of code reading are grouped into one lot, and accommodated in a cassette 7 for handling. Further, the cassette 7 is housed in a cassette case (not shown) and is transported between each process. Although there are exceptions, for convenience,
The description will proceed with one lot and one cassette.

As shown in FIG. 5, the wafer identification code 4 is an orientation flat 3 on the first main surface 2 on which the circuit pattern (not shown) of the wafer 1 is formed.
It is arranged at a position on the opposite side to and is drawn by numbers and English letters by using a means such as an etching method or a laser engraving method. Therefore, the wafer identification code 4 is substantially formed by unevenness. In the present embodiment, the wafer identification code 4 is an identification code (hereinafter, referred to as a lot code) 5 that displays a lot number of the wafer 1 and an identification code (hereinafter, a wafer code) that indicates an individual wafer number in the lot. ) 6 and.

As shown in FIGS. 1 and 5, the wafer 1 is provided with a pellet identification code 9 for identifying each pellet forming portion 8 for each pellet forming portion 8. It is also necessary to read the identification code 9. In this embodiment, the pattern for reading the pellet identification code 9 will be representatively described.

The pellet identification code 9 is the wafer 1
Since it is formed on the first main surface 2, the processing film is stacked on the pellet identification code 9 every time the wafer 1 is processed. Therefore, when the pellet identification code 9 is read by being irradiated with light as described later, the reflection condition of the irradiation light is different due to the condition and variations of the film, and thus the reading accuracy varies.

By the way, as shown in FIG. 6, the cassette 7 for accommodating the wafer 1 is provided with a large number of holding grooves (slots) S1 to S25 in a large number of stages (25 stages in this embodiment). ) The holding grooves S1 and S2 are arranged in rows.
By inserting the wafers into the respective wafers 5, a plurality of wafers (in this embodiment, one lot) are accommodated in a regularly aligned state. The cassette 7 is housed in a hermetically sealed cassette case (not shown) for transportation and storage.

In the present embodiment, one or a plurality of code reading devices 11 are installed in a module (not shown) for each process, and the code reading device 11 has the pellet identification code 9 attached to the wafer 1. Is read by optical means.

The code reading device 11 according to this embodiment includes a machine casing 12 formed in a box shape.
A loader / unloader having a loader and unloader function, a pre-alignment device, an articulated robot (hereinafter referred to as a robot) as a transfer device, and an artificial vision device are provided on the unit 2. The loader / unloader 13 is arranged on one side of the machine casing 12. The loader / unloader 13 includes an elevator 14 controlled by a controller 15. The actual cassette 7 in which a plurality of wafers 1 are stored is controlled by the elevator 14 to deliver one wafer 1 to the other, and the delivered wafers 1 1 can be returned to the original position of the cassette 7.

The pre-alignment device 17 is arranged on the machine frame 12 at a position facing the loader / unloader 13.
The positioning stage 18 and the controller 20 that controls the positioning stage 18 are provided. The alignment stage 18 brings the orientation flat 3 of the wafer 1 into contact with the linear portion 19 according to a command from the controller 20,
The wafer 1 is configured so as to have a fixed posture.

The robot 21 as a transfer device has a machine frame 12
It is arranged in the upper center position. The robot 21 has an arm 23 controlled by a controller 22, and a grip 24 for holding the wafer 1 is provided at the tip of the arm 23. The robot 21 operates the arm 23 controlled by the controller 22 to take out one wafer 1 from the real cassette 7 in the loader / unloader 13 at the grip 24, conveys the wafer 1 to the pre-alignment device 17, pre-aligns it, and then performs artificial vision. The wafer 1 is transferred to the apparatus 30, and further, the wafer 1
Is conveyed from the artificial vision device 30 to the loader / unloader 13 and is stored in the original slot of the cassette 7.

The artificial vision device 30 is arranged at one side position in the rear side portion on the machine frame 12, and the reading stage 31 is installed at the position. Reading stage 3
1 is configured to be yawed by the controller 40 with respect to the horizontal plane.

A stand 32 is erected on the machine frame 12 on one side of the reading stage 31.
An illumination device 33, an optical device 34, and a television camera 35 as a light receiving device for receiving the reflected light are supported by.
The illuminating device 33 is configured as will be described later, and the illuminating device 33 dims light of a predetermined wavelength toward the stage 31 via the optical device 34 and irradiates it. The television camera 35 is configured to capture an image of the pellet identification code 9 of the wafer 1 illuminated on the stage 31 via the optical device 34.

An identification code recognizing device 36 is electrically connected to the television camera 35. The identification code recognizing device 36 is composed of an image processing device and the like, and the television camera 3 is provided.
The pellet identification code 9 attached to the wafer 1 can be recognized based on the image pickup signal from 5. A monitor 37 is connected to the identification code recognition device 36, and the monitor 37 monitors the image pickup condition of the television camera 35.

Further, the identification code recognition device 36 is connected to a memory 38 as a recording means for successively recording the identification code, and the memory 38 stores the pellet identification code 9 recognized by the identification code recognition device 36. It is configured to record sequentially. This memory 38
Is a data processing device 3 constructed from a computer or the like
The data processing device 39 reads out the data recorded in the memory 38 at any time. The memory 38 may be installed on the data processing device 39 side.

The data processing device 39 is connected to the controller 15 of the loader / unloader 13, the controller 20 of the pre-alignment device 17, the controller 22 of the robot 21, and the controller 40 of the reading stage 31, respectively.

In this embodiment, as shown in detail in FIG. 3, the illuminating device 33 is provided with a white light source 41 containing light in a wide wavelength band, and the light source 41 is composed of an optical fiber bundle or the like. The optical waveguide 42 is opposed. Optical waveguide 42
The other end of the optical waveguide 42 is connected to the optical device 34.
An optical filter switching device 43, which is an embodiment of the present invention, is interposed in the middle of the process.

The optical filter switching device 43 is provided with a dark box 44, and in the dark box 44, a stepping motor (hereinafter, simply referred to as a motor) 45 as means for optically moving the optical filter relative to the illumination device. Is equipped. The motor 45 is configured so that its rotation is controlled by the controller 46.
Is connected to the identification code recognition device 36.

On the output shaft of the motor 45, a rotary plate 47 as a holder for holding an optical filter group is supported.
The rotary plate 47 includes a plurality of optical filters 48a to 48.
n are arranged at equal intervals in the circumferential direction on a concentric circle. The rotary plate 47 includes optical filters 48a to 48n.
The optical centers of the groups are arranged so as to substantially coincide with the optical axis of the optical waveguide 42. In addition, each optical filter 48a, 48
b, 48c, ... Are set so that the wavelengths of the transmitted light are different from each other and regularly.

Further, as shown in FIG. 3, the rotary plate 47 as an optical filter holder has a position information display 61.
The same number of a to 61n as the optical filters 48a to 48n are arranged and provided so as to correspond to the respective optical filters 48a to 48n. For example, each position information display 61
a to 61n are configured by bar codes.

On the other hand, in the dark box 44, a position information display reading device 62 as a means for detecting the optical filter currently facing the illuminating device is one of the optical filters 48a to 48n group attached to the rotary plate 47. It is equipped to face. The position information display / reading device 62 is the lighting device 3.
3 is configured to read the position information display corresponding to the optical filter which is currently opposed to No. 3, and the read position information display is transmitted to the controller 46. For example, the position information display reading device 62 is composed of a bar code reader.

In this embodiment, an illuminance control device 63 for controlling the illuminance of the light source 41 is connected to the controller 46, and the controller 46 controls the illuminance control device 6.
3 is instructed to issue an illuminance designation signal. That is, the controller 46 controls the position information display reading device 62.
The optimum illuminance is obtained for the optical filter facing the illuminating device 33 on the basis of the position information from, and a signal designating this illuminance is transmitted to the illuminance control device 63.

The illuminance control device 63 includes the optical filters 48a.about.
It has the same number of voltage setting circuits 64a to 64n as 48n, a voltage selecting circuit 65, and a voltage generating circuit 66. Then, the voltage corresponding to the illuminance designated by the designation signal from the controller 46 becomes the voltage setting circuits 64a to 64n.
The voltage is selected by the voltage selection circuit 65 and supplied to the voltage generation circuit 66. By generating the specified voltage, the voltage generation circuit 66 executes the control for causing the light source 41 to emit light with the specified illuminance.

In this embodiment, the optical device 34 is the dark box 5
1, the optical waveguide 42 is optically connected to the dark box 51. Half mirror 52 in the dark box 51
However, at the position where the optical axis of the optical waveguide 42 and the optical axis of the television camera 35 intersect, the optical waveguide 42 is arranged so as to be inclined at about 45 degrees. An objective lens 53 is arranged on the optical axis of the half mirror 52 on the side of the reading stage 31, and the lens 53 is configured so as to focus on the wafer 1 on the stage 31.

Next, the code reading device 11 according to the above configuration.
The action of will be explained.

The wafer 1 delivered from the loader / unloader 13 is transferred to the pre-alignment apparatus 1 by the robot 21.
It is transported to 7. In the pre-alignment device 17,
The wafer 1 has the orientation flat 3 and the straight portion 19
By being brought into contact with, it is adjusted to a predetermined posture.

The aligned wafer 1 is transferred to the robot 21.
Is conveyed to the reading stage 31 of the artificial vision device 30 and is transferred onto the reading stage 31 in a pre-aligned posture. On the reading stage 31, the wafer 1 is horizontally supported by the reading stage 31, and is optically faced to the illumination device 33 and the television camera 35 of the artificial vision device 30 via the optical device 34.

When the wafer 1 is faced to the illumination device 33 and the television camera 35, the artificial vision device 30 reads the pellet identification code 9 according to the flowchart shown in FIG.

If the identification code recognition device 36 cannot recognize the yaw correction signal, the yaw correction signal is first sent from the data processing device 39 to the controller 4 of the stage 31.
Sent to 0. The controller 40 of the stage 31 operates the stage 31 based on this correction signal to appropriately change and adjust the tilt angle, height, position, etc. of the wafer 1 with respect to the television camera 35.

When the recognition as the first step is not ensured, the optical filter switching signal indicates the identification code recognition device 36.
From the optical filter switching device 43 to the controller 46. The controller 46 operates the motor 45 based on the correction signal to switch from the first optical filter 48a located on the optical axis of the optical waveguide 42 to the second optical filter 48b, for example.

When the first optical filter 48a is switched to the second optical filter 48b, the position information display facing the position information display reading device 62 is also displayed as the second position information display 61b.
Therefore, the switched second position information display 61b is read by the position information display reading device 62. Second position information display 6 read
1b is transmitted to the controller 46. Controller 4
6 collates the transmitted second position information display 61b with the position information of the designated second optical filter 48b, and if they match, the first optical filter 48a becomes the second optical filter 48b. Confirm that it has been switched.

When the switch to the second optical filter 48b is confirmed, the controller 46 instructs the illuminance control device 63 to issue an illuminance designation signal corresponding to the second optical filter 48b. That is, the controller 46 determines the lighting device 3 based on the position information from the position information display reading device 62.
Optimum illuminance is obtained for the optical filter facing No. 3, and a signal designating this illuminance is transmitted to the illuminance control device 63.

In the illuminance control device 63 which has received the illuminance designation signal, the voltage corresponding to the illuminance designated by the controller 46 is selected by the voltage selection circuit 65 from the voltage setting circuits 64a to 64n to generate the voltage. It is supplied to the circuit 66. The voltage generation circuit 66 executes control to cause the light source 41 to emit light with a specified illuminance by generating a specified voltage.

For example, FIG. 7A shows the state of reflection when the pellet identification code 9 of the wafer 1 is irradiated with light having a wavelength (hereinafter, referred to as first wavelength light) 49a that has passed through the first optical filter 48a. When the identification code recognition device 36 recognizes the pellet identification code 9, the identification code recognition device 36 becomes improper.

That is, since the first wavelength light 49a is reflected by the processing film 10 on the pellet identification code 9, even if the television camera 35 receives the reflected light 50a, the contrast of the pellet identification code 9 is good. Can not be imaged. Therefore, the code recognition device 3
6 cannot recognize the pellet identification code 9 sufficiently clearly from the video signal of the television camera 35. The switching operation of the controller 46 of the optical filter switching device 43 is automatically executed based on the unrecognizable state of the code recognition device 36, that is, the situation where the contrast is poor.

Then, for example, the first optical filter 48a
Are switched to the second optical filter 48b. Light that has passed through the second optical filter 48b after being switched to the second optical filter 48b (hereinafter referred to as second wavelength light) 49.
When the state of reflection when the pellet identification code 9 of the wafer 1 is irradiated with b is as shown in FIG. 7B, the identification code recognition device 36 recognizes the pellet identification code 9 properly. .

That is, in this case, since the second wavelength light 49b is transmitted through the processing film 10 on the pellet identification code 9 and reflected by the pellet identification code 9, the television camera 35 receives the reflected light 50a. By
The pellet identification code 9 is imaged in a state where the contrast is good. Therefore, the code recognition device 36 can sufficiently recognize the pellet identification code 9 based on the video signal of the television camera 35.

By the way, when the first optical filter 48a is switched to the second optical filter 48b, the brightness (illuminance) on the reading stage 31 changes due to the different transmittance. When the brightness on the reading stage 31 changes, the imaging condition of the television camera 35 also changes, so the code recognition condition by the code recognition device 36 also changes.

Therefore, in this embodiment, when the first optical filter 48a is switched to the second optical filter 48b, the illuminance suitable for the second optical filter 48b is designated by the controller 46 as described above, and the illuminance is adjusted. The illuminance of the light source 41 is controlled by the control device 63 to an illuminance suitable for the second optical filter 48b. By controlling the illuminance, the brightness of the reading stage 31 is adjusted to be constant even after the switching to the second optical filter 48b, so that the imaging condition of the television camera 35 is maintained constant. As a result, the code recognition work by the code recognition device 36 described above is executed under certain conditions, and the accuracy of the code recognition work described above is properly secured.

After that, the switching operation for each of the optical filters 48a to 48n is repeated until the recognition of the pellet identification code 9 of the code recognition device 36 is properly executed, so that the proper operation for the pellet identification code 9 is performed as the second step. Recognition is secured.

The pellet identification code 9 read as described above is temporarily recorded in the memory 38 connected to the identification code recognition device 36. Then, by appropriately using the recorded data, the wafer data management, the physical distribution management, and the like are executed substantially in real time. The image captured by the television camera 35 is displayed on the monitor 37 and is monitored by the operator as needed.

When all the pellet identification codes 9 are read, the wafer 1 as the article to be read is unloaded from the reading stage 31 by the robot 21 and conveyed to the loader / unloader 13, as shown in FIG. , The original slot Sn in the cassette 7 of the elevator 14 of the loader / unloader 13.

According to the above described embodiment, the following effects can be obtained. (1) By appropriately changing and adjusting the wavelength of the light for illuminating the identification code of the wafer by switching the optical filter, the illumination condition of the illumination light for the identification code can be modulated for each wavelength. By switching, the best code reading situation can be created.

(2) Since the code reading device can be fully automated by automatically creating the best reading condition in the code reading device, automation of wafer data management and physical distribution management can be promoted. .

(3) The structure can be simplified by arranging such that the adjustment of the wavelength of the illumination light is executed by the switching operation of the optical filter.

(4) By configuring the optical filter switching operation to be automatically executed based on whether the image contrast is good or bad, the optical filter switching operation can be automated with a simple structure.

(5) When the optical filter to be switched is designated during the optical filter switching work, the switching operation of the designated optical filter is automatically and properly performed.
Moreover, since it can be executed in a short time, the accuracy and efficiency of the optical filter switching work can be improved.

(6) Since the brightness of the reading stage can be always kept constant by controlling the illuminance that is adapted to the switched optical filter, the television camera can always maintain a constant brightness regardless of the variation of the transmittance of the optical filter. The imaging environment can be always kept constant, and as a result, the accuracy of the code recognition work can always be properly maintained.

FIG. 8 is a schematic view showing a main part of a mark reading device according to another embodiment of the present invention.

The difference of the second embodiment from the first embodiment is that
The pattern reading device is configured as a mark reading device. That is, in this embodiment, the optical filter switching device 43A, which is one embodiment of the present invention, is used in the mark reading device 11A that reads a mark as a pattern attached to a diode.

In this embodiment, the diode 71, which is the object for reading the mark, has a mark (not shown) such as a product name and a model number, and a mark having a color for specifying the product type (hereinafter referred to as a color mark). 72 is attached. The color mark 72 is drawn using a different color for each type. For example, a high frequency diode displays a red color mark, a low frequency diode displays a blue color mark, and a small signal diode displays a green color mark.

In this embodiment, the mark reading device 11A
Is installed in the shipping process, and the color mark 72 attached to the diode 71 is read by optical means. Further, the diode 71 as the work of the mark reading device 11A is fed to the mark reading device 11A while being attached to a tape or accommodated in a magazine or another jig (not shown), The reading stage 31A to be described later is passed at high speed.

The mark reading device 11A according to the present embodiment is provided with the artificial vision device 30 having the same structure as that of the first embodiment, and the artificial vision device 30 has the diode 71 which is the article to be read at a high speed. A reading stage 31A that is passed is installed. This reading stage 31A
Is provided with a stand (not shown), and the stand supports a lighting device 33, an optical device 34, and a television camera 35 as a light receiving device for receiving reflected light. Then, the illumination device 33 dims light of a predetermined wavelength toward the stage 31A via the optical device 34 and irradiates it. The television camera 35 is configured to capture an image of the color mark 72 of the diode 71 illuminated on the stage 31A via the optical device 34.

The television camera 35 includes a mark recognition device 36.
A is electrically connected, and this mark recognition device 36
A is configured by combining a binary and grayscale image processing device. That is, the mark recognition device 36A has a low-priced structure, and the color mark 7 attached to the diode 71 based on the image pickup signal from the television camera 35.
2 is recognizable.

Further, the mark recognition device 36A is connected to a memory 38 as a recording means for sequentially recording the read results, and the memory 38 successively records the color marks 72 recognized by the mark recognition device 36A. Is configured. This memory 38 is connected to a data processing device 39 constructed from a computer or the like, and the memory 38 is connected by the data processing device 39.
The data recorded in is read out at any time. The memory 38 may be installed on the data processing device 39 side.

In this embodiment, similar to the above embodiment,
The illuminating device 33 is a white light source 4 including light of a wide wavelength band.
1, an optical waveguide 42 formed of an optical fiber bundle or the like faces the light source 41. The other end of the optical waveguide 42 is connected to the optical device 44, and an optical filter switching device 43 is provided in the middle of the optical waveguide 42.

The optical filter switching device 43 is provided with a dark box 44, and in the dark box 44, a stepping motor (hereinafter, simply referred to as a motor) 45 as means for optically moving the optical filter relative to the illumination device. Is equipped. The motor 45 is configured so that its rotation is controlled by the controller 46.
Is connected to the mark recognition device 36A.

The output shaft of the motor 45 supports a rotary plate 47 as a holder for holding the optical filter group.
The rotary plate 47 includes a plurality of optical filters 48a to 48.
n are arranged at equal intervals in the circumferential direction on a concentric circle. The rotary plate 47 includes optical filters 48a to 48n.
The optical centers of the groups are arranged so as to substantially coincide with the optical axis of the optical waveguide 42. In addition, each optical filter 48a, 48
b, 48c, ... Are set so that the wavelengths of the transmitted light are different from each other and regularly.

Further, as shown in FIG. 8, the positional information display 61 is provided on the rotary plate 47 as an optical filter holder.
The same number of a to 61n as the optical filters 48a to 48n are arranged and provided so as to correspond to the respective optical filters 48a to 48n. For example, each position information display 61
a to 61n are configured by bar codes.

On the other hand, in the dark box 44, a position information display reading device 62 as a means for detecting the optical filter currently facing the illuminating device is one of the optical filters 48a to 48n group attached to the rotary plate 47. It is equipped to face. The position information display / reading device 62 is the lighting device 3.
3 is configured to read the position information display corresponding to the optical filter which is currently opposed to No. 3, and the read position information display is transmitted to the controller 46. For example, the position information display reading device 62 is composed of a bar code reader.

In this embodiment, an illuminance control device 63 for controlling the illuminance of the light source 41 is connected to the controller 46, and the controller 46 uses the illuminance control device 6.
3 is instructed to issue an illuminance designation signal. That is, the controller 46 controls the position information display reading device 62.
The optimum illuminance is obtained for the optical filter facing the illuminating device 33 based on the position information from the, and a signal designating this illuminance is transmitted to the illuminance control device 63.

The illuminance control device 63 includes the optical filters 48a to 48a.
It has the same number of voltage setting circuits 64a to 64n as 48n, a voltage selecting circuit 65, and a voltage generating circuit 66. Then, the voltage corresponding to the illuminance designated by the designation signal from the controller 46 becomes the voltage setting circuits 64a to 64n.
The voltage is selected by the voltage selection circuit 65 and supplied to the voltage generation circuit 66. By generating the specified voltage, the voltage generation circuit 66 executes the control for causing the light source 41 to emit light with the specified illuminance.

In this embodiment, the optical device 34 is the dark box 5
1, the optical waveguide 42 is optically connected to the dark box 51. Half mirror 52 in the dark box 51
However, at the position where the optical axis of the optical waveguide 42 and the optical axis of the television camera 35 intersect, the optical waveguide 42 is arranged so as to be inclined at about 45 degrees. An objective lens 53 is provided on the optical axis of the half mirror 52 on the side of the reading stage 31A, and the lens 53 is configured so as to focus on the wafer 1 on the stage 31A.

Next, the mark reading device 11 having the above structure
The action of A will be described.

The diodes 71 attached to the tape or accommodated in a jig such as a magazine are fed to the reading stage 31A at a high speed and sequentially discharged. When the diode 71 passes through the reading stage 31A at high speed, the color marks 72 of the diode 71 are sequentially read in the reading stage 31A.

The diode 71 is the reading stage 31A.
When the color mark 72 is supplied to the lighting device 33 and the television camera 35, the artificial vision device 30 reads the color mark 72.

If the mark recognition device 36A cannot recognize the optical filter, an optical filter switching signal is sent from the mark recognition device 36A to the controller 46 of the optical filter switching device 43. The controller 46 operates the motor 45 based on the correction signal to switch from the first optical filter 48a located on the optical axis of the optical waveguide 42 to the second optical filter 48b, for example.

When the first optical filter 48a is switched to the second optical filter 48b, the position information reading device 62 is selected.
Since the position information display opposed to is also switched to the second position information display 61b, the switched second position information display 61b is read by the position information display device 62. The read second position information display 61b is transmitted to the controller 46. The controller 46 collates the transmitted second position information display 61b with the position information of the designated second optical filter 48b, and if they match, the first optical filter 48a turns the second optical filter 48b. Confirm that it has been switched to.

When it is confirmed that the second optical filter 48b has been switched to, the controller 46 commands the illuminance control device 63 to issue an illuminance designation signal corresponding to the second optical filter 48b. That is, the controller 46 determines the lighting device 3 based on the position information from the position information display reading device 62.
Optimum illuminance is obtained for the optical filter facing No. 3, and a signal designating this illuminance is transmitted to the illuminance control device 63.

In the illuminance control device 63 which has received the illuminance designating signal, the voltage corresponding to the illuminance designated by the controller 46 is selected by the voltage selecting circuit 65 from the voltage setting circuits 64a to 64n to generate the voltage. It is supplied to the circuit 66. The voltage generation circuit 66 executes control to cause the light source 41 to emit light with a specified illuminance by generating a specified voltage.

For example, when the light of the wavelength transmitted through the first optical filter 48a is blue light and the color mark 72 to be read is displayed in red, the blue light transmitted through the first optical filter 48a is displayed. Is absorbed by the color mark 72, the recognition of the red color mark 72 by the mark recognition device 36A becomes incorrect.

That is, since the blue wavelength light is absorbed by the red color mark 72, the television camera 3
In No. 5, even if the reflected light is received, the red color mark 72 cannot be imaged with a good contrast.
Therefore, the mark recognition device 36A cannot sufficiently clearly recognize the color mark 72 from the video signal of the television camera 35. Based on the unrecognizable state of the mark recognition device 36A, that is, the situation where the contrast is poor, the controller 46 of the optical filter switching device 43.
The switching operation of is automatically executed.

Then, for example, the first optical filter 48a
Are switched to the second optical filter 48b. After switching to the second optical filter 48b, if red light is transmitted though the second optical filter 48b, the red light emitted to the red color mark 72 is effectively reflected, so that the red light is emitted. The recognition of the color mark 72 by the mark recognition device 36A becomes proper.

In other words, in this case, since the red wavelength light is reflected by the red color mark 72, the television camera 35 receives the reflected light to capture the color mark 72 in a good contrast state. become. Therefore, the mark recognition device 36A can sufficiently recognize the color mark 72 based on the video signal of the television camera 35.

By the way, the optical filter 48a for blue light is used.
If the optical filter 48b for red light is switched from to, the brightness (illuminance) on the reading stage 31A changes because the transmittance is different. When the brightness on the reading stage 31A changes, the television camera 3
Since the imaging condition of No. 5 also changes, the recognition condition of the code by the mark recognition device 36A described above also changes.

Therefore, in this embodiment, the optical filter 48a for blue light to the optical filter 48b for red light is used.
Switch to the controller 4 as described above.
The illuminance adapted to the red optical filter 48b is designated by 6, and the illuminance control device 63 controls the illuminance of the light source 41 to an illuminance adapted to the red optical filter 48b. By this illuminance control, even after the optical filter 48b for red is switched to, the reading stage 31
Since the brightness at is controlled to be constant, the imaging condition of the television camera 35 is maintained constant. As a result, the mark recognition work by the mark recognition device 36A described above is executed under a certain condition, and the accuracy of the mark recognition work described above is properly secured.

Thereafter, the switching operation for each of the optical filters 48a to 48n is performed by the color mark 7 of the mark recognition device 36A.
By repeating the second recognition until it is properly executed, the proper recognition of the color mark 72 is ensured.

The data of the color mark 72 read as described above is temporarily recorded in the memory 38 connected to the mark recognition device 36A. Then, by appropriately using the recorded data, the selection inspection of the color mark 72 and the like can be executed substantially in real time. The image captured by the television camera 35 is displayed on the monitor 37 and is monitored by the operator as needed.

According to the above-mentioned embodiment, the following effects can be obtained. (1) By appropriately changing and adjusting the color (wavelength) of the light illuminating the color mark of the diode by switching the optical filter, the illumination condition of the illuminating light with respect to the color mark can be modulated for each color mark. By selecting the optical filter appropriately, the best color mark reading condition can be created.

(2) Since the mark reading device can be completely automated by automatically producing the best reading condition in the mark reading device, automation of mark inspection work and the like can be promoted.

(3) The structure can be simplified by arranging such that the adjustment of the color of the illumination light is executed by the switching operation of the optical filter.

(4) Since the optical filter switching operation is automatically performed based on whether the contrast of the image is good or bad, the optical filter switching operation can be automated with a simple structure.

(5) When the optical filter to be switched is designated during the optical filter switching work, the switching operation of the designated optical filter is automatically and properly performed.
Moreover, since it can be executed in a short time, the efficiency and accuracy of the optical filter switching work can be improved.

(6) By controlling the illuminance to suit the switched optical filter, the brightness of the reading stage can always be kept constant regardless of the transmittance of the optical filter. The environment can always be kept constant, and as a result, the accuracy of the mark recognition work can always be properly maintained.

Although the invention made by the present inventor has been specifically described based on the embodiments, the invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

The optical filter holder and the optical filter may be constructed as shown in FIGS. 9A, 9B and 9C, respectively.

The optical filter holder 47A shown in FIG. 9 (a) is formed in a rectangular plate shape, and the rectangular holder 47A has a plurality of optical filters 48.
They are lined up in a row. In the case of this embodiment, the holder 47A is moved laterally.

The optical filter holder 47B shown in FIG. 9 (b) is formed in a square plate shape, and a plurality of optical filters 48 are regularly arranged vertically and horizontally in the square holder 47B. There is. In the case of this embodiment, the holder 47B is moved in the vertical and horizontal directions.

The optical filter holder 47C shown in FIG. 9 (c) is formed in a cylindrical shape with at least one end open, and the cylindrical wall of this cylindrical holder 47C is provided with a plurality of optical filters 48. They are aligned in one row in the direction. In the case of this embodiment, the holder 47C is rotated in the circumferential direction. Then, the illumination light from the light source 41 is incident on each optical filter 48 from the outside in the radial direction, and the illumination light transmitted through each optical filter 48 is reflected by the fixed mirror 67 arranged on the center line of the holder 47C to be optically reflected. The device 34 is adapted to be illuminated.

Further, the optical filter switching device may be constructed as shown in FIG. In FIG.
The optical filter holder 47D is formed in a cylindrical shape with both ends open, and a plurality of optical filters 48 are arranged in a row in the circumferential direction on the cylindrical wall of the cylindrical holder 47D. In the case of this embodiment, the holder 47D is fixed, and the rotating mirror 68 is provided on the cylinder center of the motor 45D.
It is arranged to be rotated by. The optical filters 48a-4a are provided outside the cylindrical holder 47D.
8n, the same number of light sources 41a to 41n are used for each optical filter
8a to 48n are provided so as to face each other.

In this embodiment, when the optical filter switching command signal is transmitted from the controller 46 to the motor 45D, the rotary mirror 68 is rotated by the motor 45D, and the rotary mirror 68 is optically moved to the designated optical filter 48g, for example. Are opposed to each other. In addition, the controller 46
Transmits an illumination command to the light source 41g arranged so as to face the designated optical filter 48g.

The illumination light from the light source 41g is incident on each optical filter 48g from the outside in the radial direction, and the illumination light transmitted through the optical filter 48g is reflected by the rotating mirror 68 arranged on the center line of the holder 47D. The optical device 34 is irradiated with light.

Although not shown, the detection of the optical filter currently facing the light source is not limited to be performed by the position information display detection device, but may be directly detected from the previous command signal from the optical filter switching controller. It may be configured so as to obtain the target.

Further, the illuminance control device of the light source is not limited to the configuration as in the above-mentioned embodiment, but the power corresponding to the illuminance instruction input is stored in advance and the power corresponding to the illuminance instruction input is directly applied to the illumination light source. May be entered manually.

In the above description, the case where the invention made by the present inventor is mainly applied to the wafer code reading technique which is the field of application which is the background of the invention has been described.
The present invention is not limited to this, and can be applied to general pattern reading techniques such as an alignment target mark attached to a wafer and a circuit pattern of the wafer. Further, the pattern is not limited to the wafer pattern, and the pattern is used when the reading conditions are different because the pattern is attached to the non-read object such as a liquid crystal panel, a floppy disk, or a compact disk, and then the non-read pattern is processed. It can be applied to reading methods and devices in general.

Further, in the above description, the case where the invention made by the present inventor is mainly applied to the color mark reading technique of the diode which is the field of application which is the background has been described, but the invention is not limited thereto. The present invention can be applied to general pattern reading technology for marks and the like displayed in color on various semiconductor devices. Moreover,
The present invention can be applied not only to the pattern of the semiconductor device but also to a pattern reading method of a color pattern displayed in color such as a color mark in various general-purpose products and the device in general.

Furthermore, the optical filter switching technique is not limited to the pattern reading technique such as the code reading technique and the mark reading technique, but can be applied to other fields. In particular, the optical filter switching technique according to the present invention can be applied to an excellent effect when it is necessary to automatically switch a plurality of optical filters at a high speed.

[0119]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

By appropriately changing and adjusting the wavelength of the light illuminating the read pattern of the read object by switching the optical filter, the illumination condition of the illumination light with respect to the read pattern can be modulated for each wavelength. By selecting the filter appropriately, the best reading situation can be created.

In addition, when the optical filter to be switched is designated during the optical filter switching work, the designated optical filter switching operation can be automatically and appropriately executed in a short time. The efficiency and accuracy of the filter switching work can be improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a code reading device according to an embodiment of the present invention.

FIG. 2 is a perspective view thereof.

FIG. 3 is a front sectional view showing an optical filter switching device which is one embodiment of the present invention used in the code reading device.

FIG. 4 is a flowchart showing a code reading operation.

FIG. 5 is a plan view showing a wafer.

FIG. 6 is a perspective view showing a wafer cassette.

7 (a) and 7 (b) are explanatory views for explaining a code reading operation.

FIG. 8 is a schematic diagram showing a main part of a mark reading device that is Embodiment 2 of the present invention.

9A, 9B, and 9C are front views and perspective views, respectively, showing modified examples of the optical filter holder and the optical filter.

FIG. 10 is a schematic view showing an optical filter switching device according to another embodiment of the present invention.

[Explanation of symbols]

1 ... Wafer (article to be read), 2 ... First main surface, 3 ...
Orientation flat, 4 ... Identification code, 5 ... Lot code, 6 ... Wafer code, 7 ... Cassette, 8 ... Pellet forming section, 9 ... Pellet identification code (reading target pattern), 10 ... Processing film, 11 ... Code reading device ( Pattern reading device), 11A ... mark reading device (pattern recognition device), 12 ... machine frame, 13 ... loader / unloader,
14 ... Elevator, 15 ... Controller, 17 ... Pre-alignment device, 18 ... Alignment stage, 19 ...
Straight part, 20 ... Controller, 21 ... Robot, 22 ...
Controller, 23 ... Arm, 24 ... Grip, 30 ...
Artificial visual device, 31, 31A ... Reading stage, 32
... Stand, 33 ... Illumination device, 34 ... Optical device, 35 ...
Television camera, 36 ... Identification code recognition device, 36A ... Mark recognition device, 37 ... Monitor, 38 ... Memory, 39 ...
Data processing device, 40 ... Reading stage controller, 41 ... Light source, 42 ... Optical waveguide, 43 ... Optical filter switching device, 44 ... Dark box, 45 ... Motor, 46 ... Controller, 47 ... Rotating plate (optical filter holder), 47A ,
47B, 47C, 47D ... Optical filter holder, 48a
~ 48n ... Optical filters, 49a, 49b ... Illumination light, 5
0a, 50b ... Reflected light, 51 ... Dark box, 52 ... Half mirror, 53 ... Objective lens, 61a-61n Position information display,
62 ... Positional information display / reading device, 63 ... Illuminance control device, 6
4a to 64n ... Voltage setting circuit, 65 ... Voltage selection circuit, 6
6 ... Voltage generating circuit, 67 ... Fixed mirror, 68 ... Rotating mirror, 71 ... Diode (read target article), 72 ... Color mark (Read target pattern).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayasu Akaiwa 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Ltd.

Claims (5)

[Claims] 1. A plurality of optical filters having different transmissivities are arranged in different positions in a holder, and the holder is optically moved relative to the lighting device to optically face the lighting device. An optical filter switching method for switching the optical filter, wherein an optical filter currently facing the lighting device is detected, and the detected optical filter is designated to face the lighting device. The optical filter switching method is characterized in that the holder is optically moved relative to the illuminating device when the optical filters are compared with each other and the both do not match. 2. The optical filter switching method according to claim 1, wherein the illuminance of the illumination device is changed and adjusted in accordance with an optical filter which is currently facing. 3. A holder comprising a holder in which a plurality of optical filters respectively having different transmissivities are arranged at mutually different positions, and a moving means for optically moving the holder relative to the illumination device. Is an optical filter switching device that switches an optical filter that is optically opposed to the lighting device by being optically moved relative to the lighting device. The detecting means for detecting and the optical filter detected by the detecting means and the optical filter designated so as to face the illuminating device are collated, and when the both do not match, the moving means is used to attach the holder to the illuminating device. An optical filter switching device, comprising: a controller that transmits a movement command to optically move the optical filter relative to the optical filter. 4. A position display indicating the position of each of the optical filters is attached to the holder in advance, and the detection means detects the position display and transmits position information as the detection result to the controller. Is configured as such, the controller collates the detected position information with the position information about the optical filter designated to face the illumination light source, and when both position information do not match. 4. The optical filter switching device according to claim 3, wherein the moving means is configured to transmit a movement command to optically move the holder relative to the illumination device. 5. A pattern reading device comprising: an illuminating device that irradiates a read object on which a pattern is formed with light; and a light receiving device that receives reflected light from the read object. An optical filter switching device is provided between the device and the device. The optical filter switching device includes a holder in which a plurality of optical filters having different transmittances are arranged at different positions from each other, and the holder is a lighting device. An optical filter that switches the optical filter that is optically opposed to the lighting device by moving the holder optically relative to the lighting device. A switching device, which is a detection unit that detects an optical filter that is currently facing the lighting device, and an optical filter that is detected by the detection unit. A controller that collates with an optical filter designated to face the illumination device, and transmits a movement command to optically move the holder to the illumination device relative to the illumination device when both do not match, An optical filter switching device comprising: